1. Field of the Invention
This invention relates to an imposed order of cross-sectional and longitudinal displacement of thermo-plastic and thermo-setting materials to warm, blend and extrude the materials. More particularly, this invention concerns a screw or worm type apparatus for the warming, blending and extruding of natural and synthetic elastomeric materials. Unless otherwise indicated the terms "extruder", "extrusion apparatus" used herein refer to and include a screw or worm type apparatus used to obtain an extrudate of the desired cross-sectional configuration, and to subject the process material to an imposed order of shearing which displaces the process material in both the cross-sectional and longitudinal directions.
2. Description of Prior Art
The now conventional extruders, include a barrel, a screw type rotor within the barrel which is adapted for rotational movement relative to the barrel and a means of introducing the material to be processed into the extruder, such as a hopper and its associated apparatus, if any. The rotor is provided with various threaded configurations and rotational movement forces the material through the barrel and out of the downstream end of the extruder. Interposed between the hopper and discharge end are multiple rotor to barrel to rotor process material transfers which cross-blends the process material as it passes member to member. Longitudinal blending is very minor even to being non-existent. Thus, while process material is being discharged from the extruder, hot or cold unprocessed material is fed into the feed hopper at the opposite end of the extruder to provide a continuous process.
Examples of the prior art are U.S. Pat. No. 2,744,287 dated May 8, 1956; U.S. Pat. No. 3,632,255 dated Jan. 1, 1972; and U.S. Pat. No. 4,075,712 dated Feb. 27, 1978.
Although many problems relating to the extrusion of polymers have been solved the flow of material through the typical extruder is similar to the flow of a liquid through a pipe; first in first out. Longitudinal quality is therefor dependent on the quality of the entering material and is a parameter which this invention is designed to improve.